The Harvard University (HU) CFAR Biostatistics Core is a distributed Core, with offices at three sites: the Dana Farber Cancer Institute (DFCI), the Massachusetts General Hospital (MGH), and the Harvard School of Public Health (HSPH); these three locations provide services to all the HU CFAR institutions. The Biostatistics Core provides statistical collaboration and consultation for HIV-related laboratory, animal, clinical, and outcome studies to CFAR members and their trainees and to investigators who are new to HIV research. Broadly, the services of the biostatistics core include: design (including sample size calculations and analysis plans for all studies and database management for clinical studies), analysis of data (including model results and graphs), and training (in statistical methods, computer packages, and graphical illustration).